Pontoon boat



May 26, 1964 w. L. BOYINGTON ETAL 3, 3 ,113

PONTOON BOAT Filed June 9. 1961 INVENTORS WAYNE L. Bcynva'rau 0mm A.LINOLOFF 2s Ar-ws.

United States Patent Ofiice 3,134,113 Patented May 26, 1964 3,134,113PONTOON BOAT Wayne L. Boyington and Orrin A. Lindlolf, Wisconsin Dells,Wis. Filed June 9, 1961, Ser. No. 116,117 2 Claims. (Cl. 9-6) Thepresent invention relates generally to water craft and concerns, moreparticularly, a pontoon type boat.

It is an object of the invention to provide an improved pontoon boathaving superior performance and handling characteristics. Morespecifically, it is an object to provide a boat of this type whichexhibits excellent steering stability at all speeds, and which developsa greater speed with a motor of given horsepower than standard boats ofthis type. Steering stability refers to the ability to stay on astraight course as well as make smooth, flat turns at full throttlewithin a short turning radius. Moreover, full maneuverability isretained at slow docking or landing speeds.

A related object is to provide a boat of the above type which iseffected by wind drift to only a slight degree and, further, which iswell suited for simple and convenient bow landings and loading.

A further object is to provide a boat as characterized above which issafe, as well as easy, to handle since a minimum rolling motion isencountered and since there is no tendency of the bow to nose under thewater, even under relatively rough water conditions. An additionalsafety factor is the provision of scaled, compartmentalized pontoonhulls.

It is also an object of the invention to provide a boat of the abovecharacter which is readily adaptable for most pleasure boat usages,there being a flat deck expanse with no below-deck bilge problems.Moreover, any common type of motor including outboard, inboard, andinboard-outboard types can be readily utilized.

It is another object to provide a boat as described above which iseconomical to construct and maintain.

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to thedrawings, in which:

FIGURE 1 is a perspective of a boat constructed in accordance with thepresent invention;

FIG. 2 is a perspective of a single one of the pontoon hulls utilized inthe boat of FIG. 1;

FIG. 3 is a longitudinal section taken approximately along the line 3-3of FIG. 1 and showing an outline of the waterline when the boat isunderway;

FIGS. 4a and 4b are fragmentary sections showing the method of joiningthe pontoon components before and after assembly as seen through line 44of FIG. 3; and

FIGS. 5 and 6 are slightly enlarged sections taken approximately alongthe line 55 and 6-6, respectively, of FIG. 1.

While the invention will be described in connection with a preferredembodiment, it will be understood that we do not intend to limit theinvention to that embodiment. On the contrary, we intend to cover allalternatives, modifications and equivalents as may be included withinthe spirit and scope of the invention as defined by the appended claims.

Turning now to the drawings, there is shown a pontoon boat 10constructed in accordance with the present invention and including apair of parallel, left and right pontoons 11 and 12 which are spanned bya deck 13. In the illustrated construction, the boat includes oppositeside rails 14 and 15 and a canopy 16 mounted on the deck 13. Theexemplary boat 10 is powered by a single outboard motor 17.

In keeping with the invention, each of the pontoons or hulls 11, 12 isformed with a semicircular, opentopped, transverse cross section (seeFIGS. 5 and 6), and the deck 13 is formed of adjacent panels 21 whichsealingly close the open tops of the pontoons and hold them in rigid,spaced relation. The spacing between the opposed sides of the parallelpontoons 11, 12 is intermediate the pontoon diameter and radius andpreferably somewhat less than the diameter of the pontoon cross section.The pontoons are several times longer than their diameter, and asatisfactory length of the pontoons has been found to be approximatelyfour to five times the center-to-center spacing of the pontoons. Statedanother way, the cross sectional centers of the substantiallyemicircular pontoons are preferably spaced apart a distance equal tosomewhat less than twice the pontoon diameter.

The above stated preferred proportions for the pontoons 11, 12 have beenexperimentally determined, by trial and error methods, mainly by varyingthe spacing between pontoons. The theoretical reasons for the highdegree of handling ease and performance of the exemplary boat 10 are notcompletely understood. The maximum spacing limit appears to be the morecritical and usefully significant one since it limits the expansion ofboat size for given pontoon diameters. However, in operating a boat ofthe described proportions, it is noted that the water between the spacedpontoons 11, 12 tends to pile up when the boat is underway. Apparently,the water displaced to the left of the pontoon 11 and to the right ofthe pontoon 12 finds itself trapped between the pontoons, with theresult that the water level is raised a significant amount between thepontoons as compared to the outside water level. The upward slope ofwater level is indicated, in a typical case, by the line 25 in FIG. 3,and FIG. 6 shows the elevation of the water level line 25 with respectto the general water level, indicated by the lines 26.

It has been observed that this piling up of water between the spacedpontoons 11, 12 tends to lift the boat 10 so as to reduce the outside orapparent draft when the boat is in motion. This body of elevated wateralso seems to exert a stabilizing influence tending to hold the boat ona true straight course. When turning, the pontoon on the inside of theturning arc skids over the piled up water so as to create an addedlifting force on this pontoon. This added force appears to resist thenormal tendency of a boat to bank when turning, and, hence, the boat 10has been found to make smooth, flat turns even at full throttle andWithin a turning radius approximately equal to one and one-half timesthe length of the boat.

Because of the cylindrical conformation of the water engaging portionsof the pontoons 11, 12 and the relative shallow displacement of theboat, it can be seen that there is a maximum adjustment of the pontoonhulls to slight rolling motion of the boat so that virtually a constantwater displacement and a uniform hull relationship to the water ismaintained. With a single hull vessel such a semicylindricalconstruction would be impractical but, the shallow-draft, spacedpontoons 11, 12 of the boat 10 insure complete stability even though asemicylindrical pontoon hull configuration is used. The apparentlyobvious expedient of increasing the spacing between the pontoonsrelative to their diameter to provide the largest deck area for theconstruction cost involved has been found unsatisfactory, however, and.as previously mentioned the spacing between pontoons should not exceedthe pontoon diameter in order to retain the advantageous handlingqualities.

In addition to the above characteristics, it has been 3 found that theboat 10, having the proportions discussed, appears to develop a greaterspeed from a given horsepower motor than previous designs of this type,and also that a minimum wind drift effect is experienced. Moreover, theboat is subjected to only a slight rolling motion even in relativelyrough, choppy water.

In carrying out the invention, frusto-conical, opentopped bow portions31 and 32 are secured to the forward ends of the pontoons 11, 12,respectively, so as to constitute forwardly and upwardly extendingcontinuations of the pontoons, and a bow-deck member 21a is sealedacross the bow portions 31, 32 so as to close their open tops and definean upwardly and forwardly inclined surface with respect to the remainderof the deck 13.

While the term frusto-conical has been adopted as a convenient term forcharacterizing the shape of the bow portions 31, 32, in the interest ofgeometric accuracy a more complete description of the configuration ofthe bow portions requires mention of the fact that the sides of thesheets from which the portions are formed tend to flatten and stay invertical planes. These flattened sides have upper edges disposed at anangle with respect to the longitudinal axis of the conical bow portionsso as to support the bow-deck member 21a in its upwardly and forwardlyinclined position. The result is to give the bow portions the appearanceof being portions of tilted or oblique cones.

The bow portions 31, 32 are relatively simple and eco' nomical to form,and it has been found that they slip easily through the water with aminimum amount of turbulence. The inclined deck member 21a tends toexert a cam-.ming or planing action against the water surface whichavoids deck washing and spray and also resists any tendency of the boatnose it) down even under relatively rough conditions.

The simple strong configuration of the bow portions 31, 32 together withthe flat deck member 21a makes it possible to land the boat 10 bowforward, and to load and unload across the member 21a. Bow loading is,of course, a relatively simple operation and contributes to the ease ofwhich the boat 10 may be handled.

Pursuant to the invention, the pontoons 11, 12 are formed by a pluralityof semicircular steel bulkheads 33 alinged in parallel, spaced relationwhich sandwich a plurality of semicylindrical steel hull plates 34 thatare disposed between the bulkheads 33 with the curved edges of the hullplates abutting the bulkheads adjacent their curved sides. In thepreferred construction, the sides of the bulkheads 33 and the edges ofthe hull plates 34 are fused together by welding about the outside ofthe assembly so as to produce a single fused joint 35 (see FIGS. 4a and4b). The relatively short length of the hull plates 34 makes themeconomical toform and the outside welding process contributes to theeconomy of construction and produces a solid secure joint.

To support the deck panels 21, the straight edges of the hull plates 34and the straight edges of the bu kheads 33 are bent to define flanges 36and 37, respectively, which lie in substantially the same plane. Thedeck panels 21, preferably formed of marine plywood, are disposed flatlyon the flanges 36, 37 and are bolted directly thereto. Preferably,calking is applied between the deck panels 21 and the flanges 36, 37 soas to form a plurality of watertight compartments through the length ofthe pontoons 11, 12. This economical construction produces not only aparticularly eflicient pontoon configuration but also a very safeconstruction because of the compartrnentalized, watertight compartmentswithin the pontoons. The completely sealed pontoons 11, 12 eliminate theproblems accompanying the provision of a bilge. The

boat readily accommodates all-weather deck houses or the like as well asthe light canopy shown in FIG. 1.

In practical embodiments of the invention, hull plates 34 made of 14gauge steel have been rolled in four-foot lengths on an 18 inch radius.Plywood deck panels 21 of either eight or ten foot lengths have definedthe boat Width, and the pontoons have been located suificiently inboardof the panel ends to bring the spacing between pontoons within thedesired range. Overall boat lengths of 24 to 28 feet have provensatisfactory.

For supporting the motor 17, a bracket 40 is secured to a pair ofrearwardly extending support members 41 which are mounted on the opposedflanges 36 on the respective pontoons 11, 12. The motor 17 is clamped onthe bracket 40 in the usual manner. Alternatively, two outboard motorscan be mounted at the rear of the boat 10 on an extended bracket withone motor behind either pontoon, or the compartments defined by therearwardmost hull plates 34 and their sandwiching bulkheads 33 in eachof the pontoons 11, 12 can be used to enclose an inboard orinboard-outboard type motors to supply power for the boat 10.

A further feature illustrating the complete adaptability of the boat 10is the fact that the substantially flat deck 13 is well suited forvirtually any type of superstructure.

We claim as our invention:

1. In a pontoon boat, a pair of laterally spaced elongated pontoons eachcomprising, in combination, a plurality of semicircular bulkheads alinedin parallel spaced relation, and a plurality of semicylindrical hullplates disposed between said bulkheads with their curved edges abuttingthe bulkheads adjacent the curved sides of the bulkheads so that eachhull plate is sandwiched between a pair of bulkheads, said curved sidesand curved edges being fused together, the straight edges of saidbulkheads and said hull plates being bent to define flanges lyingsubstantially in the same plane, and a plurality of deck plates spanningsaid pair of pontoons and disposed flatly on said flanges of eachpontoon and being secured thereto for completing a series of watertightcompartments and to define a deck.

2. In a. pontoon boat, a pair of laterally spaced pontoons eachcomprising, in combination, a plurality of semicircular bulkheads alinedin parallel spaced relation, and a plurality of semicylindrical hullplates disposed between said bulkheads with their curved edges abuttingthe bulkheads adjacent the curved sides of the bulkheads so that eachhull plate is sandwiched between a pair of bulkheads, and a plurality ofdeck plates spanning said pair of pontoons and disposed flatly over thestraight edges of said bulkheads and hull plates and being securedthereto for completing a series of watertight compartments and to definea deck.

References Cited in the file of this patent UNITED STATES PATENTS979,557 Phillips Dec. 27, 1910 2,394,764 Greulich Feb. 12, 19462,396,148 Bean Mar. 5, 1946 2,453,463 Sherman Nov. 9, 1948 2,910,035Johnson Oct. 27, 1959 2,950,699 Ogden et al Aug. 30, 1960 2,975,747 OpieMar. 21, 1961 3,036,539 Storey May 29, 1962 3,045,262 Mitchell July 24,1962 FOREIGN PATENTS 414,633 France June 24, 1910 785,040 France May 13,1935

1. IN A PONTOON BOAT, A PAIR OF LATERALLY SPACED ELONGATED PONTOONS EACHCOMPRISING, IN COMBINATION, A PLURALITY OF SEMICIRCULAR BULKHEADS ALINEDIN PARALLEL SPACED RELATION, AND A PLURALITY OF SEMICYLINDRICAL HULLPLATES DISPOSED BETWEEN SAID BULKHEADS WITH THEIR CURVED EDGES ABUTTINGTHE BULKHEADS ADJACENT THE CURVED SIDES OF THE BULKHEADS SO THAT EACHHULL PLATE IS SANDWICHED BETWEEN A PAIR OF BULKHEADS, SAID CURVED SIDESAND CURVED EDGES BEING FUSED TOGETHER, THE STRAIGHT EDGES OF SAIDBULKHEADS AND SAID HULL PLATES BEING BENT TO DEFINE FLANGES LYINGSUBSTANTIALLY IN THE SAME PLANE, AND A PLURALITY OF DECK PLATES SPANNINGSAID PAIR OF PONTOONS AND DISPOSED FLATLY ON